The current international system with its emphasis on state sovereignty was designed to restrain interference in domestic affairs by other states. However, this notion has been repeatedly challenged throughout the past 70 years by states intervening with military instruments in internal armed conflicts. Possible motives that led states to jeopardize the lives of their soldiers and convinced them to bear the costs of interventions have engendered a rich debate in the studies of International Relations and Peace and Conflict Studies. In this dissertation, two arguments based on the logic of the realist theory of international relations are brought forward to augment our understanding of factors contributing to military interventionism. First, it is shown that economic linkages between states transcend the debate on trade and include the effects of foreign direct investment on their willingness to intervene by force. Corporate investment is shown to significantly raise the willingness of states to intervene when existing FDI is endangered by the dynamics unfolding during internal armed conflicts. Second, great powers are apt to harness other states to alter the conflict dynamics in civil wars. Applying the principal-agent framework in combination with the logic of arms trade allows identifying unequal...

La décision d’intervenir militairement ou non dans un conflit est certainement l’une des plus importantes qu’un État puisse prendre. Ces décisions sont coûteuses et très prégnantes tant au plan financier, politique que social. La recherche exposée vise à analyser les processus décisionnels canadiens en matière d’intervention militaire lors de la guerre du Golfe, la guerre en Afghanistan ainsi que la guerre en Irak. Le Canada est un cas très intéressant à étudier, car malgré son statut de puissance moyenne, il a pris part à sept conflits armés depuis 1867. Cette recherche tentera donc de déterminer ce qui motive le Canada à investir des ressources financières et humaines dans certains conflits, alors qu’il choisit de ne pas s’impliquer dans d’autres. Certaines théories des relations internationales affirment que la politique de défense des États est guidée par le désir de maximiser leur puissance sur la scène internationale. D’autres théories mettent plutôt l’accent sur les valeurs des États, ou bien sur leur intégration dans des institutions internationales. Ces différentes hypothèses soulèvent l’importance des facteurs internes et externes, mais ne permettent pas de savoir lesquels priment. Ainsi, grâce à un modèle de prise de décision réaliste néoclassique, synthétisant ces deux types de facteurs, il est possible de déterminer lesquels des éléments internes (contraintes de politique interne, perception des dirigeants) ou externes (position relative du Canada dans le système international) prédominent lors de la décision d’entrer ou non en guerre. / The decision to intervene militarily or not in a conflict is certainly one of the most important a government can take. These decisions are extremely significant financially, politically and socially costly. The research presented in this document analyzes decision-making processes in Canada during the Gulf War, the war in Afghanistan and the war in Iraq. Canada is a very interesting case to study because despite its middle power status, it took part in seven armed conflicts since September 1867. This research will therefore try to identify the reasons for Canada to invest financial and human resources in some conflicts, while it chooses not to get involved in others. Some theories of international relations argue that the defence policy of states is guided by the desire to maximize their power on the international stage. Other theories will instead focus on values or norms internalized by states, or their integration into international institutions. These different assumptions raise the importance of internal and external factors, but do not tell which will prevail. Thus, using a neoclassical realism model of decision making synthesizing these two factors, it will be possible to determine which internal (internal policy constraints, perceptions of managers) or external factors (Canada's relative position in the international system) dominate in the decision to go to war.

[pt] Esta dissertação trata dos processos decisórios de política externa que levaram os EUA a intervirem na República Dominicana no ano de 1965 e a URSS a intervir na Tchecoslováquia em 1968. Procuro analisar como a política doméstica das superpotências influenciou suas políticas externas, estudando as motivações dos diversos grupos dentro destes Estados e, principalmente, a forma pela qual se produziu consenso em torno das intervenções militares. Explico que as decisões foram tomadas a partir de considerações sobre a tática mais apropriada para ampliação ou, no mínimo, manutenção do poder relativo destes Estados. Procuro demonstrar, portanto, que as divergências entre os grupos domésticos no que se refere às decisões táticas podem dificultar e até inviabilizar esforços de política externa dos Estados, mas que estes grupos têm um interesse comum, que é definido em termos de poder relativo do Estado em que se inserem. Com os resultados desta análise, podemos avaliar a vantagem, em termos de capacidade explicativa, do realismo neoclássico em relação ao paradigma liberal quando se trata de teorizar sobre política externa na área de segurança. / [en] This dissertation concerns the decisionmaking processes of foreign policy which led to the interventions of the United States in the Dominican Republic in 1965 and the USSR in Czhecoslovakia in 1968. I analyze how the superpowers` domestic politics influenced their foreign policies, studying the motivations of numerous internal groups and, mainly, how consensus around the military interventions was produced. I explain that those decisions were a result of considerations about the most appropriate tactics for enhancing or, at least, maintaining the relative power of those States. I try to demonstrate, therefore, that divergences between domestic groups over tactic decisions may hinder a State`s efforts on foreign policy, but those domestic groups have a common interest, which is defined in terms of their State`s relative power. With the results of this analysis, we can evaluate the advantage of neoclassical realism, as opposed to the liberal paradigm, in terms of explaining power when it comes to matters of national security policies.

La décision d’intervenir militairement ou non dans un conflit est certainement l’une des plus importantes qu’un État puisse prendre. Ces décisions sont coûteuses et très prégnantes tant au plan financier, politique que social. La recherche exposée vise à analyser les processus décisionnels canadiens en matière d’intervention militaire lors de la guerre du Golfe, la guerre en Afghanistan ainsi que la guerre en Irak. Le Canada est un cas très intéressant à étudier, car malgré son statut de puissance moyenne, il a pris part à sept conflits armés depuis 1867. Cette recherche tentera donc de déterminer ce qui motive le Canada à investir des ressources financières et humaines dans certains conflits, alors qu’il choisit de ne pas s’impliquer dans d’autres. Certaines théories des relations internationales affirment que la politique de défense des États est guidée par le désir de maximiser leur puissance sur la scène internationale. D’autres théories mettent plutôt l’accent sur les valeurs des États, ou bien sur leur intégration dans des institutions internationales. Ces différentes hypothèses soulèvent l’importance des facteurs internes et externes, mais ne permettent pas de savoir lesquels priment. Ainsi, grâce à un modèle de prise de décision réaliste néoclassique, synthétisant ces deux types de facteurs, il est possible de déterminer lesquels des éléments internes (contraintes de politique interne, perception des dirigeants) ou externes (position relative du Canada dans le système international) prédominent lors de la décision d’entrer ou non en guerre. / The decision to intervene militarily or not in a conflict is certainly one of the most important a government can take. These decisions are extremely significant financially, politically and socially costly. The research presented in this document analyzes decision-making processes in Canada during the Gulf War, the war in Afghanistan and the war in Iraq. Canada is a very interesting case to study because despite its middle power status, it took part in seven armed conflicts since September 1867. This research will therefore try to identify the reasons for Canada to invest financial and human resources in some conflicts, while it chooses not to get involved in others. Some theories of international relations argue that the defence policy of states is guided by the desire to maximize their power on the international stage. Other theories will instead focus on values or norms internalized by states, or their integration into international institutions. These different assumptions raise the importance of internal and external factors, but do not tell which will prevail. Thus, using a neoclassical realism model of decision making synthesizing these two factors, it will be possible to determine which internal (internal policy constraints, perceptions of managers) or external factors (Canada's relative position in the international system) dominate in the decision to go to war.